UP CLOSE AND PERSONAL WITH MR. MECHIELSEN
Robert Mechielsen – "The Art of Carbon-Neutral Design"
The art of designing the Hi'ilani EcoHouse, located on the Big Island of Hawaii, required merging and maximizing the client's requirements and desired views and determining the most efficient structural design, while calculating the precise geometry and composition of the "Butterfly"-shaped SCIP roofs which allow for harvesting the energy of the elements to nuture the house. Maximizing the views then gave rise to the composition of rooms and spaces, on top of which we installed a structurally-sound SCIP roof.
The key issue that inspired my design for the Hi'ilani EcoHouse grew from the fact that the house had no water source. Installing a traditonal thatched-roof, as we all know, would enable water to flow down the two descending roof sides and eventually run its course into a rain gutter; however I started to foresee problems with this process-- as an example, the clogging of rain gutters by leaves and debris. That, in turn, provided the inspiration for implementation and installation of a Butterfly-shaped roof, where the roof edges rise inverted and upward, resulting in a "V" shape, where water could be collected in its natural valley.
The butterfly-shaped roof represents a radical departure from a traditional thatched roof, which has been used since man started building dwellings. Whereas a thatched roof's primary function is to keep water away from the house and to protect it from the elements, the butterfly-shaped roof's purpose is to receive and collect water, which then, in combination with solar and wind energy, nuture and empower the house.
The Hi'ilani's sleek and easily identifiable seven butterfly-roofs cascade upon one another for easy water collection, use tradewinds to regulate the interior climate and allow for a variety of solar panel installations hidden out of sight.
I explored the idea of making the roof more aerodynamic in order to take advantage of the island's natural tradewinds to keep the roof free of debris. I realized that butterfly-shape acts similarly to an air foil of an airplane-- creating negative air pressure under the roof-- which could be used to draw air circulation throughout the entire house.
The SCIP roof works as a thermal sandwich, with insulating foam in the center, and sheets of 2" concrete on top and bottom. The thermal storage of the bottom concrete sheet captures the cold night air, which is then used to cool the house during the next hot day.
The tradewinds move over the roofs and create the negative air pressure-- resulting in a natural suction effect-- and pull the cold air under the ceiling. By adding remote controlled intake louvres, the temperature can be adjusted room by room with an automitzed climate control system, which maintains the desired temperature throughout the house. What is rermarknble here is that the nature of employing SCIP to build the house structurally has a dual purpose of providing a free thermal storage device, as well as allowing for climate control.
The butterfly shape also allows the roof to house the solar hot water heating system, a cycle which begins with the collection of rain water (stored in a 26,000 gallon underground tank), which is filtered, pressurized and heated using solar power. The cycle is completed as the water returns to the ground through leech fields and then can is used for landscaping.
”The most fantastic thing about carbon neutral living is that you never have to feel guilty about using any resources”.
As Appeared in INHABITAT
STUDIO RMA'S HI'ILANI ECOHOUSE IS AMERICA'S FIRST CARBON-NEUTRAL CONCRETE STRUCTURE, AND IT'S VOLCANO-ADJACENT!
Hawaii is paradise, but building a home there takes an experienced hand and a strong working knowledge of its unique climate and geology. Overlooking the Pacific Ocean, the 4,000 sq. foot Hi’ilani EcoHouse gets a lot of warming sun in the day time, but ocean breezes cause the temperature to drop drastically at night. Achieving carbon-neutral status hinged on Mechielsen’s ability to trap and repurpose the cool air that occurs naturally after sunset. The unique nature of long-lasting SCIP panels made this possible.
Often made of recycled plastic or metal, SCIP foam contains 90 percent air, which accounts for its terrific insulating properties. SCIP panels have a similar strength to 8” solid concrete or concrete block structures, although they use 60% less cement.
“These panels have an insulating core of EPS foam with a structural wire-mesh space frame stitched through the foam,” explains a press release. “Once the panels are connected to form the shell of the house they are sprayed off with a concrete-plaster mix, similar to stucco, creating the structural strength and the finish of the exterior and interior walls. Its vast cantilevered overhangs are completely made with SCIP only with additional rebar.” Thus the house is virtually wood and metal-free.
This unique construction material means that the Hi’ilani EcoHouse’s cooling is accomplished entirely by storing night-time cool temperatures in the insulated concrete ceiling plates for next day use. Fans distribute the cool air, while a computer system opens and closes motorized glass louvers, further controlling the temperature in the house.
Staying naturally cool isn’t the only benefit of the Hi’ilani EcoHouse’s unique construction, however. Because the house is built from concrete, it’s virtually invisible to the ever-present termites that love to feast on wood structures. This means that no toxic pest-control treatments are necessary. If you’re not in love with the color grey, it’s easy to augment the SCIP panels with lime plasters and even soy based stains to create a rich color and texture palette. And remember that nearby active volcano? Well it turns out that SCIPs are incredibly stable, and quickly becoming a favorite among Caribbean home owners who often face hurricanes, or in this case, seismic activity.
Being carbon neutral requires more than just special concrete and eco-friendly paint, of course. The Hi’ilani EcoHouse’s wing-shaped structure cleverly hides powerful solar arrays. The wings also harvest the rainwater and act just like the foils of an airplane wing catching the trade-winds to cool the building.
The home has a host of interesting features including a 25,000 gallon water-holding tank that doubles as an outdoor stage, an in-house spa, a media room and a music recording facility. And don’t think the carbon-neutral aspect of the Hi`ilani EcoHouse is limited to the construction: Even the CO2 emitted to build the home, including flying crews in, will be off-set by the creation of a 3-acre native dense forest.